PHOENIX—No player wants to move backward in an organization's pecking order.

That's what happened to lefthander Zach Jackson in 2007, and he didn't like it much. He had taken a step forward the previous season with his first exposure to the big leagues, going 2-2, 5.40 in eight outings that helped stabilize an injury-riddled rotation.

Jackson, 24, found himself on the outside looking in last season, failing to get a return invitation to Milwaukee. He spent the entire season with Triple-A Nashville, struggling to an 11-10, 4.46 record while allowing an alarming 184 hits in 170 innings.

"Last year was a frustrating year," he said. "But, looking at the big picture, I learned a lot about my game and myself, and broadening my repertoire.

"When I got called up in '06, it was an amazing opportunity. It was more like battling and competing with all I had. All I really had was a fastball and cutter. And I didn't have great command of those."

If he ever wanted to don a Brewers uniform again, Jackson was told he needed to come up with a reliable offspeed pitch to keep hitters off his hard stuff. He took that direction to heart and has worked hard on a "split changeup" that, as described, works a bit like a splitter and a bit like a changeup.

"I have them beating the ball into the ground; that works for me," he said. "I'm not a strikeout pitcher. I'm a contact guy. I try to miss as many barrels as I can."

In his first two spring outings, Jackson pitched five innings without allowing an earned run, and appeared to be a more confident pitcher.

"Instead of worrying about mechanical stuff, I'm just going out there and getting outs," said Jackson, a supplemental first-round pick of the Blue Jays out of Texas A&M in 2004 who came over in the Lyle Overbay trade a year later.

"It's more fun because you have all these weapons in your arsenal. I have something different to show the hitters."

MICROBREWS

• Righthander Scott Cassidy, invited to major league camp as a non-roster player, announced his retirement the day after allowing four runs to the Rockies in less than an inning.

• Catcher Lou Palmisano will miss three to four months after having surgery to repair a torn meniscus in his left knee.